To avoid the cumulative morbidity and mortality associated with initial palliative procedures followed by later repair, primary corrective surgery has become increasingly common for patients with congenital heart disease. One result of this trend is that an increasing number of cardiac surgical procedures are performed on neonates and even on premature infants. Optimal care of these infants requires specialized knowledge of the unique structural and functional characteristics of neonatal organ systems and is best accomplished by a multidisciplinary specialty team including cardiology, cardiac surgery, nursing, neonatology, anesthesia, and critical care. The purpose of this chapter is to review general principles of care for these infants. The physiology and surgical procedures pertinent to specific defects are discussed in Chapters 6 through 8. Medications commonly used in the postoperative period are discussed in Chapter 12.
OVERVIEW OF CARDIAC SURGICAL PROCEDURES
Cardiac surgical procedures are classified as to whether they are open or closed and whether they are corrective or palliative (Table 13-1). “Open” refers to a procedure in which cardiopulmonary bypass is used; bypass is not used in “closed” procedures. Palliative procedures are performed in patients in whom complete correction of the cardiac defects is not possible or not feasible because of comorbidities. Palliated patients have residual intracardiac shunting or other hemodynamic abnormalities. In most institutions, palliative procedures are performed only on infants with a functional single ventricle (eg, hypoplastic left heart syndrome, tricuspid atresia) or on those with poorly developed pulmonary arteries.
TABLE 13-1.Classification of Cardiac Surgery Procedures ||Download (.pdf) TABLE 13-1. Classification of Cardiac Surgery Procedures
|Closed: Cardiopulmonary bypass is not used. |
| Palliative—Pulmonary artery band, systemic-to-pulmonary artery shunt |
| Corrective—Repair of aortic coarctation, ligation of patent ductus arteriosus |
|Open: Cardiopulmonary bypass is used. |
| Palliative—Stage I Norwood procedure, Damus-Kaye-Stansel procedure |
| Corrective—Repair of transposition of the great arteries, tetralogy of Fallot, total anomalous pulmonary venous connection, truncus arteriosus, ventricular septal defect |
|Examples of palliative and corrective procedures are provided, but these lists are not comprehensive. |
Most corrective procedures, such as for truncus arteriosus or transposition of the great arteries, are performed by use of cardiopulmonary bypass. Bypass diverts blood from the operative field while maintaining circulation, adds oxygen and removes carbon dioxide from the blood, and facilitates cooling and subsequent warming. Venous blood from both superior and inferior vena cavae is siphoned to a reservoir of the heart-lung bypass machine, which also collects blood drained from the operative field by suction catheters (Figure 13-1). Blood is pumped through an oxygenator, a heat exchanger (for cooling or warming), and a filter and then is returned to the patient’s ascending aorta through an aortic cannula. The patient is always fully anticoagulated with heparin while on bypass.
Diagram of basic cardiopulmonary bypass system.